Method for sampling molten metal



Feb. 22, 1966 KOOKEN 3,236,103

METHOD FOR SAMPLING MOLTEN METAL Filed Sept. 12, 1963 IIVI/EIVTO/P FREDKOO/(EN A f/arney United States Patent 3,236,103 METHOD FOR SAMPLINGMOLTEN METAL Fred F. Kooken, Hammond, Ind., assignor to United StatesSteel Corporation, a corporation of Delaware Filed Sept. 12, 1963, Ser.No. 308,501 2 Claims. (Cl. 73425.2)

This invention relates to the taking of a sample from a pool of moltenmetal and, in particular, to a method therefor.

The sampling of molten metal, e.g., steel, as teemed from a ladle intothe conventional ingot mold, has heretofore been effected by throttlingthe stream from the ladle as the level of molten metal in the mold risesto the maximum desired height, and holding a dip spoon in the stream.The sample thus collected is poured into a cast iron mold to provide aspecimen for analysis. This procedure is open to serious objections buthas continued in use, nevertheless, for lack of anything better.

In the first place, the diminished stream from the ladle, the handlingof the sample in the spoon and the pouring therefrom all increase thepossibility of atmospheric oxidation. As a result, the specimen analyzeslower in certain contents such as manganese, than the ingot itself. Thishas led to the discard of many ingots for failure to meet specificationwhen they were actually within the ranges required in respect to certainelements, as shown by subsequent check analyses of the ingots. A furtherobjection is that the samples form heavy skulls in the spoonnecessitating violent abuse thereof attempting to clear them for anothersample. Thus spoon life is short and the cost of spoons is substantial.In addition, there is a distinct safety hazard in collecting samplesfrom a teeming stream.

I have invented a novel method of sampling ingots as cast. My methodinvolves dipping a sample holder into the top of a mold or other vesselcontaining molten metal. The problem of obtaining a representativesample by dipping is complicated by the fact that slag and otherimpurities normally float on the surface of the liquid metal makingdifficult the lifting of a clean sample therefrom. In fact, it has beengenerally agreed that a sample dipped from the surface could not betruly representative. My investigation and further analysis, however,have proved that this view was erroneous. On the contrary, samples takenin accordance with my invention have proved highly representative ofingot chemistry on comparison with check analyses of specimens takenfrom the ingot after freezing and stripping of the mold therefrom.

In a preferred practice of my method, I insert bottom first a tubularsample holder, closed at the bottom, open at the top and having afilling port intermediate the top and bottom, downwardly through theslag floating on the liquid metal and into the latter until the port isbelow the surface thereof. I hold it therein three or four seconds withthe top of the holder projecting above the slag layer. The holder isquickly filled with clean molten metal and any slag or floatingimpurities drawn in with it rise to the surface. The upper end of theholder projecting above the floating slag and impurities prevents theirentry. The holder is then lifted out of the molten metal and the slagfloating thereon, with the result that excess metal in the holder andany entrapped slag flows out through the port. The thickness of theholder wall is such that the clean metal left in the holder is notimmediately chilled but is solidified in a minute or so after Withdrawalby air cooling. Thereafter the holder and metal therein are cut throughtransversely, affording one or more specimens as desired.

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The holder is preferably formed from a length of steel pipe and shouldhave a substantial wall thickness to withstand immersion in molten metalfor a few seconds without loss of integrity, but should not be so heavyas to act as a chill mold.

A complete understanding of the invention may be obtained from thefollowing detailed description and explanation which refer to theaccompanying drawings illustrating the present preferred embodiment ofthe sample holder. In the drawings, the single figure is an elevation ofmy sample holder with parts broken away and in section, to reveal theinterior.

Referring now in detail to the drawing, the holder 10 is conveniently alength of steel pipe closed at the bottom by pinching, compression orflattening as indicated at 14. The upper end of the holder is open andfits snugly but removably in a carrier collar 12. The holder is securedin the collar by a set screw 17, in abutment against an internal seatingshoulder or ring 16. A handle 13 has one end bent at an angle 18 and isattached to collar 12 as by welding. Filling ports 15 are formed bydrilling transversely through the holder intermediate its ends. Thedepth of the holder below the ports should be sufficient to provide asample of the desired size and the height above the ports should sutficeto extend from a level well below the surface of the molten metal to alevel above the surface of the floating slag.

Upon use in the manner already explained, the holder and sample in thelower portion, after solidification of the latter and removing theholder from collar 10, are cut through transversely to providemetallurgical specimens. Although the holder is thus destroyed after asingle use, it is expendable because it is so cheap that the costthereof is not a substantial item.

In a typical example of the holder disclosed, it was formed from a 12"length of common steel pipe 1.25" in outside diameter having a Wallthickness of about .0 The ports 15 were about A" in diameter. The bottomwas closed by pinching or flattening in a press for about /2" from oneend.

The invention is useful in taking samples from a tapping ladle as wellas from an ingot mold since conditions are quite similar in both cases,i.e., a pool of molten metal with slag or impurities floating on thesurface.

My invention has other advantages in addition to affording arepresentative sample of clean metal and reducing the cost incident tothe use of sampling spoons. The wall thickness of the holder is suchthat the sample cools relatively slowly on being removed from the moltenmetal yet avoids the segregation which occurred in the mold used withthe stream-dipping practice by spoons. The invention also reduces thehazard to personnel collecting the samples as compared with streamdipping. It further makes possible a final correction of ingotcomposition by additions to the ingot mold while the contents are stillmolten, because the samples can be observed and tested at the pouringfloor by known means and methods, within a few minutes after beingtaken.

Although I have disclosed herein the preferred practice of my invention,I intend to cover as well any change or modification therein which maybe made without departing from the spirit and scope of the invention.

I claim: I

1. A method of securing a solidified sample of molten metal from a poolthereof having slag floating on its surface, comprising lowering bottomfirst into the pool a tubular holder having a closed bottom, an open topand a filling port intermediate the top and bottom, until said port isbelow the surface of the metal, while keeping the top of holder abovethe surface of the slag, whereby the portion of the holder above theport prevents the entry .top of the holder above the surfaceof the slag,whereby the tom and the -port, thereb'y affording a specimen for 10metallurgical analysis and inspection.

References Cited by the Examiner UNITED STATES PATENTS Sargent 73-425.4Splaine 141-110 Jones 2283 Reeve 22-209 Peine 73425.2

J. SPENCER OVERHOLSER, Primary Examiner.

MARCUS U. LYONS, Examiner.

UNITED sTATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,236,103 February 22, 1966 Fred Fe Kooken It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 3, line 1, strike out "top of the holder above the surface of theslag, whereby the".

Signed and sealed this 31st day of January 1967.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer Commissioner of Patents EDWARD J.BRENNER

1. A METHOD OF SECURING A SOLIDIFIED SAMPLE OF MOLTEN METAL FROM A POOLTHEREOF HAVING SLAG FLOATING ON ITS SURFACE, COMPRISING LOWERING BOTTOMFIRST INTO THE POOL A TUBULAR HOLDER HAVING A CLOSED BOTTOM, AN OPEN TOPAND A FILLING PORT INTERMEDIATE THE TOP AND BOTTOM, UNTIL SAID PORT ISBELOW THE SURFACE OF THE METAL, WHILE KEEPING THE TOP OF HOLDER ABOVETHE SURFACE OF THE SLAG, WHEREBY THE PORTION OF THE HOLDER ABOVE THEPORT PREVENTS THE ENTRY TOP OF THE HOLDER ABOVE THE SURFACE OF THE SLAG,WHEREBY THE OF SLAG, THEN, WHEN THE PORTION OF THE HOLDER BELOW THE PORTHAS BEEN FILLED WITH METAL, RAISING THE HOLDER ABOVE THE SURFACE OF THEPOOL, PERMITTING ANY SLAG AND EXCESS METAL THEREIN TO ESCAPE THROUGHSAID PORT, AND THEN ALLOWING THE HOLDER AND THE METAL REMAINING THEREINTO COOL UNTIL THE LATTER SOLIDIFIES.